카페인 (운동 전)

The effect of caffeine on subsequent sleep: A systematic review and meta-analysis.

1. Sleep Med Rev. 2023 Jun;69:101764. doi: 10.1016/j.smrv.2023.101764. Epub 2023 Feb 6. The effect of caffeine on subsequent sleep: A systematic review and meta-analysis. Gardiner C(1), Weakley J(2), Burke LM(3), Roach GD(4), Sargent C(4), Maniar N(5), Townshend A(1), Halson SL(1). Author info

Comparing Acute Effects of Caffeine Delivery Forms on Cross-Training Performance: A Randomized Placebo-Controlled Crossover Trial.

2. Nutrients. 2026 Feb 17;18(4):657. doi: 10.3390/nu18040657. Comparing Acute Effects of Caffeine Delivery Forms on Cross-Training Performance: A Randomized Placebo-Controlled Crossover Trial. Vargas-Molina S(1)(2), Bonilla DA(2)(3), García-Sillero M(1), Iglesias-Placed S(4), Murri M(5)(6)(7)(8)

Pre-workout multi-ingredients or carbohydrate alone promote similar resistance training outcomes in middle-aged adults: a double-blind, randomized controlled trial.

3. J Int Soc Sports Nutr. 2025 Dec;22(1):2519515. doi: 10.1080/15502783.2025.2519515. Epub 2025 Jun 13. Pre-workout multi-ingredients or carbohydrate alone promote similar resistance training outcomes in middle-aged adults: a double-blind, randomized controlled trial. Puente-Fernández J(1), Lar

Comparative effects of caffeine, beta-alanine, and their combination on mechanical, physiological, and perceptual responses to upper-body superset resistance training.

4. Eur J Appl Physiol. 2025 Mar;125(3):837-850. doi: 10.1007/s00421-024-05639-4. Epub 2024 Oct 22. Comparative effects of caffeine, beta-alanine, and their combination on mechanical, physiological, and perceptual responses to upper-body superset resistance training. Martos-Arregui A(1), Li Z(1)

The Effect of Acute Pre-Workout Supplement Ingestion on Basketball-Specific Performance of Well-Trained Athletes.

5. Nutrients. 2023 May 14;15(10):2304. doi: 10.3390/nu15102304. The Effect of Acute Pre-Workout Supplement Ingestion on Basketball-Specific Performance of Well-Trained Athletes. Douligeris A(1), Methenitis S(1)(2)(3), Lazou A(4), Panayiotou G(5), Feidantsis K(1), Voulgaridou G(1), Manios Y(6)(7)

The effects of a caffeine containing pre-workout supplement on β(2)-adrenergic and MAPK signaling during resistance exercise.

6. Eur J Appl Physiol. 2023 Mar;123(3):585-599. doi: 10.1007/s00421-022-05085-0. Epub 2022 Nov 16. The effects of a caffeine containing pre-workout supplement on β(2)-adrenergic and MAPK signaling during resistance exercise. Nicoll JX(1), Fry AC(2), Mosier EM(3). Author information: (1)Departme

Effects of Theacrine as a Pre-Workout Supplement.

7. Int J Environ Res Public Health. 2022 Oct 28;19(21):14037. doi: 10.3390/ijerph192114037. Effects of Theacrine as a Pre-Workout Supplement. Cerqueira HSC(1), Filho HT(2), Corrêa Junior M(1), Martinelli Junior CE(1). Author information: (1)Ribeirao Preto Medical School, University of Sao Paulo,

The Effect of a Multi-Ingredient Pre-Workout Supplement on Time to Fatigue in NCAA Division I Cross-Country Athletes.

8. Nutrients. 2021 May 27;13(6):1823. doi: 10.3390/nu13061823. The Effect of a Multi-Ingredient Pre-Workout Supplement on Time to Fatigue in NCAA Division I Cross-Country Athletes. Fye H(1), Pass C(1), Dickman K(1), Bredahl E(1), Eckerson J(1), Siedlik J(1). Author information: (1)Department of

Androgen and glucocorticoid receptor phosphorylation following resistance exercise and pre-workout supplementation.

9. Steroids. 2021 Aug;172:108859. doi: 10.1016/j.steroids.2021.108859. Epub 2021 May 8. Androgen and glucocorticoid receptor phosphorylation following resistance exercise and pre-workout supplementation. Nicoll JX(1), Fry AC(2), Mosier EM(3). Author information: (1)California State University,

Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis.

1. J Int Soc Sports Nutr. 2026 Dec 31;23(1):2663363. doi: 10.1080/15502783.2026.2663363. Epub 2026 Apr 24. Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis. Yao J(1), He J(2), Hu E(3). Author information: (1)School of Physical Education, China University of Mining and Technology, Xuzhou, China. (2)School of Physical Education and Training, Capital University of Physical Education and Sports, Beijing, China. (3)College of Aviation and Sports, Civil Aviation Flight University of China, Deyang, China. BACKGROUND AND OBJECTIVES: Esports place exceptional demands on neuropsychological capacities; however, a systematic and quantitative synthesis of the specific efficacy of nutritional interventions across various tasks and competitive populations remains absent. This study aims to evaluate the impact of nutritional supplementation on cognitive function and competitive performance in esports players and to explore key moderating variables. METHODS: Electronic databases, including Web of Science, PubMed, and Scopus, were searched (up to January 25, 2026). Thirteen randomized controlled trials (RCTs) met the inclusion criteria. A three-level random-effects model was employed to calculate the pooled effect size (Hedges' g), with sources of heterogeneity explored through subgroup analyses and meta-regression. RESULTS: Nutritional interventions significantly enhanced esports-related performance (g = 0.92), with the most pronounced benefits observed in processing speed (g = 1.18) and executive function (g = 1.06). Subgroup analyses revealed significant gains in both professional (g = 0.97) and amateur groups (g = 0.92), while the improvement in first-person shooter (FPS) games (g = 0.96) appeared to surpass that in multiplayer online battle athlete (MOBA) games. Meta-regression indicated no significant linear correlation between caffeine dosage and effect size. GRADE assessment categorized the quality of evidence mostly as "low" to "moderate." CONCLUSIONS: Nutritional interventions demonstrate significant potential for optimizing multidimensional cognitive performance in esports players, particularly in enhancing fundamental reaction speed and high-level decision-making processes. While the findings exhibit a degree of robustness, their practical application should be cautiously evaluated within specific competitive contexts due to current limitations in evidence certainty and significant interstudy heterogeneity. Future research characterized by gender balance and mechanistic orientation with long-term intervention protocols is warranted to elevate the level of clinical evidence. DOI: 10.1080/15502783.2026.2663363 PMCID: PMC13112869 PMID: 42028821 [Indexed for MEDLINE] Conflict of interest statement: No potential conflict of interest was reported by the author(s).

Comparative effects of caffeine and paraxanthine on rowing performance and sleep quality: a randomized crossover study.

2. J Int Soc Sports Nutr. 2026 Dec 31;23(1):2650339. doi: 10.1080/15502783.2026.2650339. Epub 2026 Mar 31. Comparative effects of caffeine and paraxanthine on rowing performance and sleep quality: a randomized crossover study. Bingol Diedhiou A(1), Yildirim UC(2), Ozdenk S(3), Erkan D(4), Karakulak I(5), Yildirim Tuncer S(6), Turğut M(3), Gundem MC(3), Bora MV(5), Akca F(7). Author information: (1)Department of Coaching Education, School of Physical Education and Sports, Şırnak University, Şırnak, Türkiye. (2)Department of Coaching Education, Faculty of Sport Sciences, Sinop University, Sinop, Türkiye. (3)Department of Sport Management, Faculty of Sport Sciences, Sinop University, Sinop, Türkiye. (4)Department of Physical Education and Sports, Institute of Health Sciences, Ankara University, Ankara, Türkiye. (5)Department of Sport Management, Faculty of Sport Sciences, Mardin Artuklu University, Mardin, Türkiye. (6)Department of Coaching Education, Faculty of Sport Sciences, Lokman Hekim University, Ankara, Türkiye. (7)Department of Coaching Education, Faculty of Sport Sciences, Ankara University, Ankara, Türkiye. BACKGROUND: Although caffeine is widely used in athletes due to its ergogenic effects, the effects of its main metabolite, paraxanthine, on performance and sleep have not been adequately investigated. PURPOSE: This study aimed to comparatively investigate the effects of caffeine and its main metabolite paraxanthine on rowing performance and sleep quality. METHODS: The study was designed as a randomized, double-blind, crossover study and included 14 male university-level rowers (21.6 ± 1.9 age; 2.2 ± 1 years of rowing experience). The participants participated in 2000-m rowing ergometer time trials under four different supplementation conditions (caffeine + paraxanthine, caffeine + placebo, paraxanthine + placebo, and placebo with 200  mg each). Performance data (completion time, mean power, and heart rate), sleep quality, and daytime sleepiness were assessed by subjective scales. The data were analyzed by repeated-measures analysis of variance (ANOVA) and Bonferroni post-hoc tests. RESULTS: Compared with the placebo, the combined caffeine + paraxanthine condition was associated with faster 2000-m performance and higher mean power output (p = 0.044; Cohen's d = 0.30). Caffeine alone and paraxanthine alone did not show clear evidence of performance improvement in this sample, although estimates favored both conditions versus placebo. Conditions containing caffeine were associated with poorer subjective sleep quality, whereas paraxanthine alone showed more favorable sleep-related outcomes. CONCLUSION: These results indicate that the combined ingestion of caffeine and paraxanthine elicited the most pronounced performance benefits, while paraxanthine alone did not demonstrate clear standalone ergogenic efficacy at the administered dose. However, paraxanthine was associated with better subjective sleep outcomes compared to caffeine, suggesting that its potential value may be related more to tolerability rather than superior performance enhancement, particularly for athletes training in the evening. Study limitations, including the small sample size and lack of objective sleep measures, should be considered when interpreting the results. PRACTICAL APPLICATIONS: Paraxanthine may represent a practical option for athletes who prioritize sleep quality or experience sensitivity to caffeine-related sleep disturbances, although further dose‒response studies are required to clarify its ergogenic potential. DOI: 10.1080/15502783.2026.2650339 PMCID: PMC13045172 PMID: 41918248 [Indexed for MEDLINE] Conflict of interest statement: No potential conflict of interest was reported by the author(s).

Caffeine Supplementation Increases Muscle Strength, but Not Endurance, While Both Caffeine and Its Expectation Elevate Blood Lactate: A Balanced-Placebo Design Study.

3. Nutrients. 2026 Feb 28;18(5):801. doi: 10.3390/nu18050801. Caffeine Supplementation Increases Muscle Strength, but Not Endurance, While Both Caffeine and Its Expectation Elevate Blood Lactate: A Balanced-Placebo Design Study. Soares EMKVK(1)(2), da Cruz CJG(2)(3), Ives SJ(1), Molina GE(2), Fontana KE(2). Author information: (1)Department of Health and Human Physiological Sciences, Skidmore College, Saratoga Springs, NY 12866, USA. (2)Exercise Physiology Laboratory, Universidade de Brasília, Brasilia 70910-900, DF, Brazil. (3)Cardiac Autonomic Function Research Group, Centro Universitário Euro Americano-UNIEURO, Brasilia 71900-100, DF, Brazil. Objectives: To determine whether caffeine supplementation and its expectancy influence muscle strength (ST) and muscle endurance (ME) using a balanced-placebo design. Methods: Using a randomized, double-blind, balanced-placebo design, resistance-trained men (18-30 years; n = 16) participated in two assessment/familiarization visits (demographics; one repetition maximum (1RM) followed by four counterbalanced sessions: C/C (informed caffeine/used caffeine), P/C (informed placebo/used caffeine), C/P (informed caffeine/used placebo), P/P (informed placebo/used placebo). Caffeine dose was 5 mg/kg. Peak torque (PT) and maximum work (MW) were measured in the knee extensors at 0, 60, 180, and 300°/s, which was followed by ME testing (three sets of maximal repetitions using 60%1RM). Capillary blood lactate was measured after ME testing. Results: Caffeine increased PT only during static and 60°/s contractions (4%; p ≤ 0.003; d = 0.3 for both speeds), while MW increased across all speeds (4%; p < 0.001; d = 0.2). Caffeine did not increase ME (3%; p = 0.184; d = 0.1), but it did increase blood lactate levels (1.2 mmol/L; p < 0.001; d = 0.7). Caffeine expectation did not improve ST or ME, but increased blood lactate levels (0.7 mmol/L; p = 0.003; d = 0.4). Across ST and ME, responses to caffeine were markedly heterogeneous, with 50-88% of individuals considered responders (∆ > 0), and improvements in responders ranged from 1-16%. Conclusions: Caffeine significantly increased ST, despite ME increasing in 50% of participants, this was not significant. No placebo effect was observed in ST or ME, but it significantly increased lactate. Further research is necessary to elucidate the mechanisms behind this variability in the ME response, especially the role of fiber-type predominance. DOI: 10.3390/nu18050801 PMCID: PMC12986729 PMID: 41829971 [Indexed for MEDLINE] Conflict of interest statement: The authors declare no conflicts of interest.

Effects of Acute Caffeine Supplementation on Integrated Biathlon Performance in Elite Male Athletes.

4. Int J Sport Nutr Exerc Metab. 2026 Feb 9;36(2):109-118. doi: 10.1123/ijsnem.2025-0138. Print 2026 Mar 1. Effects of Acute Caffeine Supplementation on Integrated Biathlon Performance in Elite Male Athletes. Engel H(1), Yilmaz C(1), Appelhans D(1), Staunton CA(2)(3), Kock H(2)(4), Mathieu J(4), Leitlauf T(5), Brandl R(5), Waibel K(6), Koehler K(1). Author information: (1)Department of Health and Sport Sciences, TUM School of Medicine and Health, Technical University of Munich, Munich, Germany. (2)Swedish Winter Sports Research Center, Department of Health Sciences, Mid Sweden University, Östersund, Sweden. (3)Department of Environmental and Bioscience, School of Business, Innovation and Sustainability, Halmstad University, Halmstad, Sweden. (4)Institute for Applied Training Science, Leipzig, Germany. (5)Olympic Training Center Thuringia, State Sports Federation Thuringia, Erfurt, Germany. (6)German Ski Association, Planegg, Germany. Caffeine enhances endurance performance but may impair shooting accuracy, creating a potential trade-off for overall biathlon performance. In a randomized, placebo-controlled, crossover study, seven elite male biathletes consumed caffeine (3 mg/kg) or taste-matched placebo 60 min before a simulated biathlon competition consisting of five "laps" of 6-min treadmill skiing interspersed by four five-shot bouts. Participants further performed precision shooting (20 prone and 20 standing) pre- and postcompetition. Caffeine increased distance covered in Laps 1 (1,824 ± 73 vs. 1,772 ± 66 m; p = .03, dz = 1.12) and 2 (1,801 ± 92 vs. 1,776 ± 84 m; p = .02, dz = 1.19) but did not improve total distance (p = .06). Blood lactate (p = .01, ηp2=.85) and ventilation (p < .001, ηp2=.90) increased with caffeine. Heart rate (p = .07) and perceived exertion (p = .69) did not differ between conditions. Caffeine impaired shooting accuracy in standing (72.9 ± 16.0% vs. 82.9 ± 7.6%; p = .03, dz = 0.87), but not prone. Integrated race times did not differ between conditions for individual (71.72 ± 5.27 vs. 71.58 ± 4.57 min), mass start (52.45 ± 3.67 vs. 52.57 ± 3.27 min), or pursuit (44.18 ± 3.18 vs. 44.23 ± 2.83 min; all p > .77) formats. Caffeine impaired postexercise precision shooting in prone position (88.9 ± 6.0% vs. 93.3 ± 7.5%; p = .04, dz = 0.65). Our findings highlight task-specific effects of caffeine, emphasizing the importance of tailoring supplementation to integrated performance demands. DOI: 10.1123/ijsnem.2025-0138 PMID: 41666907 [Indexed for MEDLINE]

CYP1A2 Genotype and the Ergogenic Effect of Acute Caffeine Intake on Muscular Strength and Endurance Performance in Trained Individuals.

5. Scand J Med Sci Sports. 2026 Feb;36(2):e70214. doi: 10.1111/sms.70214. CYP1A2 Genotype and the Ergogenic Effect of Acute Caffeine Intake on Muscular Strength and Endurance Performance in Trained Individuals. Montalvo-Alonso JJ(1), Del Val-Manzano M(1), Martín-Rivas I(1), Ferragut C(1), Valadés D(1), Pérez-López A(1). Author information: (1)Departamento de Ciencias Biomédicas, Área de Educación Física y Deportiva, Facultad de Medicina y Ciencias de la Salud, Universidad de Alcalá, Madrid, España. This study examined whether CYP1A2 (rs762551) genotype modulates the acute ergogenic effects of caffeine on muscular strength and endurance performance in resistance-trained men and women. Ninety-four resistance-trained participants (47 females, 47 males; 39 AA, 44 AC, 11 CC) completed a randomized, triple-blind, placebo-controlled, crossover trial. Participants ingested 3 mg/kg of caffeine or placebo before performing standardized bench press and back squat tests. Mean velocity was measured to assess strength performance against different loads (25%-90%) and muscular endurance during a single set performed to failure at 65% 1RM. Data were analyzed using ANCOVA with supplement, genotype, and sex as factors. Caffeine significantly improved strength and endurance performance across conditions (p < 0.01, ηp2  = 0.077-0.294). Mean velocity increased by 4%-12% in AA and 3%-9% in AC individuals, particularly at 50%-90% 1RM, whereas CC carriers showed minor changes (≤ 4%). Supplement by genotype interaction was noted only at 90% 1RM in mean velocity (p < 0.05, ηp2  = 0.094). In the muscular endurance test, mean velocity improved by 4%-6% in AA, 3%-4% in AC, and 2%-6% in CC. No sex differences or ergolytic effects were observed. Acute ingestion of 3 mg/kg caffeine enhances strength and endurance performance in resistance-trained men and women. Although CYP1A2 genotype did not alter the overall effect, benefits were greatest in AA, intermediate in AC, and minimal in CC carriers. These findings support low-dose caffeine as an effective and safe ergogenic aid in resistance training regardless of sex, with individual variability partly explained by genotype. © 2026 The Author(s). Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd. DOI: 10.1111/sms.70214 PMCID: PMC12863236 PMID: 41627185 [Indexed for MEDLINE] Conflict of interest statement: The authors declare no conflicts of interest.

Effects of Carbohydrate Combined with Caffeine on the Sports Performance of Basketball Players.

6. Am J Mens Health. 2026 Jan-Feb;20(1):15579883251412111. doi: 10.1177/15579883251412111. Epub 2026 Jan 31. Effects of Carbohydrate Combined with Caffeine on the Sports Performance of Basketball Players. Cheng X(1), Ji N(1), Zhang L(1), Zhu W(2), Jia B(3). Author information: (1)Blockchain and Healthcare, Health Service Research Center Xi'an, Xi'an Medical University, Xi'an, China. (2)School of physical education, Xi'an Physical Education University, Xi'an, China. (3)Faculty Education College, Shaoxing University, Shaoxing, China. The purpose of this study is to investigate the effects of combined carbohydrate (CH) and caffeine (CAF) supplementation on the sports performance of basketball players. A randomized crossover controlled experimental design was employed. A total of 32 collegiate-level basketball players were randomly assigned to one of the four groups: placebo (PLA), CH (30 g/h glucose solution) group, CAF (3 mg/kg body mass) group, and CH + CAF (combined intervention) group. Participants underwent a series of tests, including the countermovement jump (CMJ), 20-m sprint (20 m), change-of-direction and acceleration test (CODAT), Yo-Yo intermittent recovery test level 1 (Yo-Yo), free throw (FT) test, and straight-line dribbling speed (SLDS) test. Heart rate (HR) and blood lactic acid (BLA) levels were also monitored during the tests. The results revealed that, in the CMJ, 20 m, and CODAT tests, the CAF and CH + CAF groups outperformed the PLA group significantly (p < .05). In the Yo-Yo test, both the CH and CH + CAF groups demonstrated significantly better performance compared with the PLA group (p < .01). However, no significant differences were observed among the groups in the FT and SLDS tests (p > .05). Notably, the BLA levels in the CAF group were significantly higher than those in the PLA and CH groups 1-min postexercise (p < .05), and also significantly higher than in the CH + CAF group (p < .01). Three min after exercise, BLA levels in both the CH + CAF and PLA groups increased significantly (p < .05), with the CH + CAF group showing a greater increase compared with the CH group (p < .01). During exercise, the HR in the CH group was significantly lower than in the PLA group (p < .01), while the HR in the CAF group was significantly higher than in the PLA group (p < .01). Furthermore, the HR in the CH group was significantly lower compared with the CAF group (p < .01), and the HR in the CH + CAF group was significantly higher than in the CAF group (p < .01). After exercise, the HR in the CH group remained significantly lower than in the CAF group (p < .01). In conclusion, the combined supplementation of CH + CAF can effectively improve the overall sports performance of basketball players, with a certain recovery effect on physiological responses, but has no significant impact on professional skills. Overall, joint supplementation has not shown significant synergistic effects, but it can still be used as one of the nutritional strategies, with flexible selection of usage based on actual needs. DOI: 10.1177/15579883251412111 PMCID: PMC12861393 PMID: 41618893 [Indexed for MEDLINE] Conflict of interest statement: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Nutritional supplements to improve esports player performance: a systematic review of randomized controlled trials.

7. J Int Soc Sports Nutr. 2026 Dec 31;23(1):2603303. doi: 10.1080/15502783.2025.2603303. Epub 2025 Dec 22. Nutritional supplements to improve esports player performance: a systematic review of randomized controlled trials. Huang D(1), Zheng Y(1), Xu M(1), Huang W(2). Author information: (1)College of Physical Education, Jiangxi University of Technology, Nanchang, People's Republic of China. (2)College of Physical Education, Jiangxi Normal University, Nanchang, People's Republic of China. BACKGROUND: Esports has become a globally popular competitive activity. The performance of esports athletes depends not only on daily skill training but also on cognitive function, reaction speed, and psychological mood. In recent years, nutritional supplements have attracted widespread attention as a potential adjunctive treatment. However, their actual effects lack systematic evaluation. Objective: The primary aim of this study is to comprehensively review existing evidence and assess the impact of nutritional supplements on the performance of esports athletes, including cognitive, psychological, and gaming aspects. METHODS: As of June 17, 2025, randomized controlled trials (RCTs) or randomized crossover trials investigating the effects of nutritional supplements on cognitive function, psychological mood, and competitive performance in esports players were retrieved from the PubMed, Scopus, Web of Science, and Embase databases. Two researchers independently extracted key information and data from the literature. The methodological quality of the included studies was assessed using the Physical Therapy Evidence Database (PEDro) scale. RESULTS: A total of 13 randomized controlled trials were included, comprising 10 randomized crossover trials and 3 randomized controlled trials. The study population comprised 466 participants. The methodological quality of the studies, assessed by the PEDro scale (score range 6-10), was good to excellent. The studies included 18 nutritional supplement protocols, with 14 protocols involving pure caffeine or caffeine-containing supplements. Other protocols included active substances such as inositol-enhanced arginine silicate (ASI + I), γ-aminobutyric acid (GABA), and microalgae extracts. Based on existing evidence, some nutritional supplements are associated with three aspects of competitive performance among esports players: 1) Esports players demonstrate significant improvements in attention and executive function, which are closely related to gaming. 2) Improvements in esports players' psychological mood are manifested as increased vitality and reduced fatigue/negative emotions. 3) Improvements in gaming performance are primarily focused on shooting performance, such as increased shooting scores and accuracy, as well as reduced reaction times. CONCLUSION: Specific nutritional supplements may improve esports players' cognitive function, psychological mood, and gaming performance.However, these findings represent preliminary evidence based on the heterogeneity of the included studies and raise concerns regarding the overall risk of bias in over half of the research. Furthermore, the small sample sizes and focus on amateur players limit the generalizability of the results. Consequently, caution is warranted when interpreting these findings.Future clinical studies are needed to standardize supplementation protocols, dosage, and measurement methods to confirm the benefits of nutritional supplements for esports players. DOI: 10.1080/15502783.2025.2603303 PMCID: PMC12724221 PMID: 41424341 [Indexed for MEDLINE] Conflict of interest statement: The authors declare that they have no conflict of interest.

Effects of Nutritional Supplements on Explosive Lower Limb Performance in Volleyball Players: A Systematic Review and Network Meta-Analysis.

8. Nutrients. 2025 Nov 26;17(23):3702. doi: 10.3390/nu17233702. Effects of Nutritional Supplements on Explosive Lower Limb Performance in Volleyball Players: A Systematic Review and Network Meta-Analysis. Du H(1), Liu S(2), Li M(3), Zhao K(4), Jiang W(4), You T(2), Wang Z(5), Zou D(6), Shu J(1), Liu C(2). Author information: (1)Department of Physical Education, China Agricultural University, Beijing 100193, China. (2)School of Sport Science, Beijing Sport University, Beijing 100084, China. (3)Volleyball Administrative Center, Beijing Muxiyuan Sports Technical School, Beijing 100075, China. (4)China Volleyball College, Beijing Sport University, Beijing 100084, China. (5)Career and Entrepreneurship Services, Beijing 100084, China. (6)Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China. Background: Explosive lower limb power, a critical determinant of success in volleyball, is a prime candidate for focused research. Consequently, nutritional supplements are commonly employed to gain an ergogenic edge. Despite this widespread practice, a comprehensive and evidence-based ranking of supplements for improving this key attribute is lacking, leaving athletes and practitioners without targeted evidence to guide decisions. Methods: PubMed, Web of Science, CENTRAL, and Embase were searched from inception to 1 August 2025. We included RCTs in volleyball athletes (≥14 years) with ≥1-week interventions and relevant explosive lower limb performance outcomes. A Bayesian NMA estimated effects with 95% credible intervals (CrIs) and SUCRA; certainty was appraised with CINeMA. Results: A total of 35 RCTs (n = 838 volleyball athletes) examining 13 different supplements were included. The results indicated that β-alanine was associated with the greatest improvement in vertical jump (MD 4.6; 95% CrI 1.2-7.8), followed by creatine (MD 3.7; 0.57-6.9) and caffeine (MD 2.1; 0.06-4.1). It also appeared to be the most promising method for substantially increasing lower limb peak power (SMD 1.1; 0.21-2.0). No statistically significant improvement was found in lower limb mean power, and no serious adverse events were reported. Conclusions: Among volleyball athletes, β-alanine appeared most promising effective supplement for enhancing key components of explosive lower limb performance, specifically vertical jump height and peak power. Creatine and caffeine are also effective for improving vertical jump height. However, these findings are based on low-to-moderate certainty of evidence; they should be interpreted with caution and regarded as preliminary. Supplement strategies should be individualized by age and competitive level; further, high-quality, standardized randomized controlled trials are warranted to validate these initial observations. DOI: 10.3390/nu17233702 PMCID: PMC12694113 PMID: 41373993 [Indexed for MEDLINE] Conflict of interest statement: The authors declare no conflicts of interest.

How does acute caffeine ingestion affect maximal strength and muscular power in bench press and back squat in resistance-trained men?

9. J Int Soc Sports Nutr. 2025 Dec 31;22(1):2587791. doi: 10.1080/15502783.2025.2587791. Epub 2025 Nov 26. How does acute caffeine ingestion affect maximal strength and muscular power in bench press and back squat in resistance-trained men? Ma Y(1), Chen Y(2), Ding L(1), Xiao Y(3), Lei TH(4), Barnes M(5), Guo L(6), Cao Y(1), Girard O(7). Author information: (1)School of Athletic Performance, Shanghai University of Sport, Shanghai, People's Republic of China. (2)Department of Rehabilitation Medicine, Huashan Hospital, Fudan University, Shanghai, People's Republic of China. (3)Physical Education Teaching and Research Department, Hunan Institute of Technology, Hengyang, People's Republic of China. (4)College of Physical Education, Hubei Normal University, Huangshi, People's Republic of China. (5)School of Sport, Exercise and Nutrition, Massey University, Palmerston North, New Zealand. (6)School of Exercise and Health, Shanghai University of Sport, Shanghai, People's Republic of China. (7)School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Perth, Australia. OBJECTIVE: This study examined whether caffeine (4 mg/kg) enhances upper- and lower-body maximal strength and muscular power by increasing muscle recruitment and reducing in ratings of perceived exertion (RPE) and pain perception. METHODS: Fourteen resistance-trained males completed two randomized trials involving either caffeine ingestion (4 mg/kg) or a placebo. Sixty minutes after ingesting capsule, participants performed maximal strength tests (one-maximum repetition [1RM]) followed by muscular power assessments (bar velocity and power output) at 25%, 50%, 75%, and 90% of 1RM, performing 3, 2, 1, and 1 repetitions, respectively during bench press and back squat. Outcome measured included 1RM, mean and peak velocity, mean and peak power output, surface electromyographic activity of the prime movers, RPE, and pain perception. RESULTS: Compared to placebo, caffeine significantly increased 1RM in both bench press and back squat, while reducing RPE and pain perception and enhancing root mean square (RMS) activity in the gluteus maximus (all p < 0.05), though it did not affect the median frequency (MDF) or mean frequency (MF) in any studied muscle (all p > 0.05). The percent improvement in 1RM was larger (+7.0 ± 2.9% vs. + 4.1 ± 2.9%; p < 0.05) for the back squat than for the bench press. Furthermore, caffeine significantly increased muscular power during both exercises (all p < 0.05), without affecting surface electromyographic activity of the prime movers, RPE, and pain perception (all p > 0.05). CONCLUSION: Ingesting a caffeine capsule at a dose of 4 mg/kg enhances maximal strength by increasing muscle recruitment and reducing RPE and pain perception, with greater improvement observed in the bench press than in the back squat. Caffeine also improves muscular power in both exercises without altering muscle recruitment or subjective perception. DOI: 10.1080/15502783.2025.2587791 PMCID: PMC12667307 PMID: 41297920 [Indexed for MEDLINE] Conflict of interest statement: The authors declare that they have no competing interests.

Influence of the CYP1A2 genotype on the exercise performance of physically active individuals under caffeine supplementation: a systematic review.

10. Nutr Res. 2025 Dec;144:16-31. doi: 10.1016/j.nutres.2025.10.005. Epub 2025 Oct 16. Influence of the CYP1A2 genotype on the exercise performance of physically active individuals under caffeine supplementation: a systematic review. Messenburger GP(1), Nuñez FF(2), Porepp O(3), Collares LDN(1), Delpino FM(4), de Barros CC(5), Pieniz S(6). Author information: (1)College of Nutrition, Federal University of Pelotas, Pelotas, RS, Brazil. (2)Postgraduate Program in Food and Nutrition, College of Nutrition, Federal University of Pelotas, Pelotas, RS, Brazil. (3)Postgraduate Program in Medical Sciences: Endocrinology, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil. (4)Postgraduate Program in Health Sciences, College of Nursing, Federal University of Pelotas, Pelotas, RS, Brazil. (5)College of Nutrition, Federal University of Pelotas, Pelotas, RS, Brazil; Postgraduate Program in Food and Nutrition, College of Nutrition, Federal University of Pelotas, Pelotas, RS, Brazil. (6)College of Nutrition, Federal University of Pelotas, Pelotas, RS, Brazil; Postgraduate Program in Food and Nutrition, College of Nutrition, Federal University of Pelotas, Pelotas, RS, Brazil. Electronic address: nutrisimone@yahoo.com.br. This study aims to evaluate the influence of the CYP1A2 genotype on the exercise performance of athletes and physically active individuals with caffeine supplementation. We followed the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. The search was performed up to May 2025 and included the following databases: PubMed, EMBASE, Scopus, Web of Science, Cochrane Central Register of Controlled Trials, CINAHL, LILACS, and SPORTDiscus. Only randomized clinical trials evaluating the effects of caffeine supplementation and the influence of the CYP1A2 genotype on exercise performance were included. The risk of bias was evaluated using the updated version of the Cochrane tool for assessing bias risk in randomized trials (RoB 2). We included 19 studies, involving 732 participants, and published between 2012 and 2024. Dosages of caffeine supplementation ranged from 2 to 9 mg/kg. Although there is no consensus among all studies, caffeine supplementation has shown positive results in sports performance in individuals with the AA genotype, as well as positive for AC individuals with smaller effect sizes, and null or negative for individuals with the CC genotype. The majority (84%) of the included studies were classified as "some concerns" in our risk of bias analysis, with only two studies classified as having a low risk of bias. Caffeine may enhance athletic performance in various sports modalities and physical tests in individuals with the AA genotype, may also demonstrate marginal improvement in AC individuals, and has null or detrimental effects on individuals with the CC genotype. Copyright © 2025 Elsevier Inc. All rights reserved. DOI: 10.1016/j.nutres.2025.10.005 PMID: 41207073 [Indexed for MEDLINE] Conflict of interest statement: Author declarations All authors declare no conflict of interest in this manuscript. All authors had access to the data.

Caffeine Supplementation and Hair: A Systematic Review.

11. J Drugs Dermatol. 2025 Nov 1;24(11):1070-1074. doi: 10.36849/JDD.8902. Caffeine Supplementation and Hair: A Systematic Review. Ly N, Paiewonsky B, Fruechte S, Goldfarb N, Hordinsky MK, Bakker C, Sadick N, Arruda S, Farah RS. BACKGROUND: While caffeine has been proposed to stimulate hair growth, its safety and efficacy remain unclear. This systematic review evaluates the effects of caffeine interventions on hair loss and growth outcomes. METHODS: A systematic review of seven databases, including PubMed, Medline, and Embase, was conducted in August 2023. Original studies investigating caffeine's effects on hair loss were included. Study quality was assessed using the National Institute of Health Study Quality Assessment Tools. Outcomes of interest included caffeine intervention types and their effects on hair growth. RESULTS: Of 587 citations, nine studies met the inclusion criteria: five randomized controlled trials, three prospective cohort studies, and one twin-twin cohort study. Most studies investigated topical caffeine; one assessed oral caffeine intake. Topical caffeine consistently demonstrated hair growth or reduced hair loss with minimal adverse effects. However, none of the studies used tattooed or marked scalp areas for hair counts. CONCLUSIONS: Caffeine appears to be a safe and promising potential treatment for hair loss. Topical caffeine shows potential as a therapeutic option, though further large-scale randomized controlled trials with standardized outcome measures are needed. DOI: 10.36849/JDD.8902 PMID: 41187241 [Indexed for MEDLINE]

Influence of coffeeberry extract on soccer specific skill performance during simulated soccer match-play and following fatiguing exercise in academy players.

12. J Sci Med Sport. 2026 Feb;29(2):185-194. doi: 10.1016/j.jsams.2025.09.001. Epub 2025 Sep 9. Influence of coffeeberry extract on soccer specific skill performance during simulated soccer match-play and following fatiguing exercise in academy players. Rodriguez-Giustiniani P(1), Rollo I(2), Pahnke M(3), O'Brien L(4), Grant G(5), Desbrow B(6), Galloway SDR(7). Author information: (1)Brighton and Hove Albion Football Club, United Kingdom; Faculty of Health Sciences and Sport, University of Stirling, United Kingdom. (2)Gatorade Sports Science Institute, PepsiCo Life Sciences, United Kingdom. (3)Gatorade Sports Science Institute, PepsiCo Life Sciences, United States. (4)Department of Sport, Exercise and Nutrition, Atlantic Technological University, Ireland. (5)School of Pharmacy and Medical Sciences, Griffith University, Australia. (6)School of Health Sciences and Social Work, Griffith University, Australia. (7)Faculty of Health Sciences and Sport, University of Stirling, United Kingdom. Electronic address: s.d.r.galloway@stir.ac.uk. OBJECTIVES: To investigate the effects of acute coffeeberry extract ingestion on soccer-specific technical skill performance, sprint performance, high-intensity running capacity, and subjective perceptions of fatigue, energy, and alertness during a soccer match simulation in academy soccer players. DESIGN: Double-blind, randomised, placebo-controlled, crossover trial. METHODS: Twenty trained male soccer players completed two experimental trials (coffeeberry extract [300 mg] and placebo [flavour and colour matched] beverages), separated by 7-14 days. Each trial, conducted 1 h after ingestion of the test beverages, included a 45-min half soccer match simulation incorporating dribbling, sprinting, and passing tasks, followed 5 min later by a high-intensity running-to-fatigue protocol. Subjective measures (fatigue, mental/physical energy), physiological data (glucose, lactate), technical skills and running outcomes were assessed. Blood samples were analysed for chlorogenic acid and caffeine concentrations. RESULTS: Coffeeberry ingestion resulted in greater maintenance of passing speed (p < 0.01) and accuracy (p < 0.01) compared to placebo, most evident on short passes. No meaningful significant differences were observed in sprint performance, dribbling or running capacity. Subjective fatigue increased, and energy scores declined, similarly across trials. No difference was observed in blood glucose or lactate responses. No chlorogenic acid or caffeine was detected at quantifiable concentrations in plasma samples post-ingestion. CONCLUSIONS: Acute ingestion of coffeeberry extract improved select aspects of soccer skill performance, particularly short-passing speed/accuracy, in academy soccer players. These findings suggest a potential cognitive or neuromuscular mechanism, independent of metabolic effects. Further research is warranted to explore the time course of chlorogenic acid absorption and its potential mechanistic role in skill performance. Copyright © 2025 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. DOI: 10.1016/j.jsams.2025.09.001 PMID: 40993029 [Indexed for MEDLINE] Conflict of interest statement: Declaration of interest statement IR and MP are employees of the Gatorade Sports Science Institute, a division of PepsiCo Inc. The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of PepsiCo Inc. No other authors have any competing interests to declare.

Performance-enhancing effects of caffeine and L-Theanine among Iranian elite wrestlers: a focus on cognitive and specific physical performance.

13. J Int Soc Sports Nutr. 2025 Dec;22(1):2564238. doi: 10.1080/15502783.2025.2564238. Epub 2025 Sep 22. Performance-enhancing effects of caffeine and L-Theanine among Iranian elite wrestlers: a focus on cognitive and specific physical performance. Razazan R(1), Hemmatinafar M(1), Imanian B(1), Jahaniboushehri N(1), Rezaei R(1), Nazemzadegan G(1). Author information: (1)Shiraz University, Department of Sport Science, Faculty of Education and Psychology, Shiraz, Iran. BACKGROUND: Caffeine is a well-known ergogenic aid that can enhance physical and cognitive performance. However, it often induces side effects, such as anxiety and overstimulation, which can be problematic in high-pressure sports like wrestling. L-theanine, a non-stimulant amino acid found in tea, may help mitigate these effects by promoting a calm yet focused mental state. This study aimed to investigate the acute effects of caffeine, L-theanine, and their combination on physical performance, cognitive function, and anxiety in elite male wrestlers. METHODS: In a double-blind, placebo-controlled, crossover design, 12 elite male wrestlers (21.8 ± 2.1 years) completed four test sessions under randomized conditions: placebo (PLA), caffeine (CAF; 3 mg/kg), L-theanine (THE; 3 mg/kg), and caffeine + L-theanine (CAF+THE; 3 mg/kg each). After 60 minutes, athletes performed the wall-squat test, vertical jump height (VJH), medicine ball throw (MBT), handgrip strength, and the Specific Wrestling Fitness Test (SWFT). Cognitive function was assessed pre- and post-SWFT using a computerized Stroop test. Anxiety was assessed using the State-Trait Anxiety Inventory (STAI), and side effects were recorded. RESULTS: CAF+THE outperformed PLA in wall-squat time (p = 0.001), MBT (p = 0.005), VJH (p = 0.011), and grip strength (p = 0.004). SWFT throw count was highest in CAF+THE versus all other conditions (p < 0.001). Post-SWFT Stroop reaction time was faster in CAF+THE than PLA (p = 0.004) and THE (p = 0.036), and accuracy was also higher (p = 0.009 vs PLA). CAF alone increased state anxiety compared to PLA (p = 0.021), while CAF+THE reduced anxiety to below placebo levels (8% incidence vs 33%). Trait anxiety was lower in CAF+THE compared to CAF (p = 0.018). The prevalence of caffeine-induced tachycardia (92%) was notably reduced under CAF+THE (17%). CONCLUSION: CAF+THE (3 mg/kg each) enhances elite wrestlers' strength, endurance, cognitive speed, and accuracy while reducing anxiety and physiological side effects commonly associated with caffeine alone. This combination represents a safe, practical supplement strategy for combat sports athletes who must maintain explosive performance and mental control under stress. Coaches are encouraged to trial CAF+THE protocols during training to personalize timing and dosage. DOI: 10.1080/15502783.2025.2564238 PMCID: PMC12456047 PMID: 40977612 [Indexed for MEDLINE] Conflict of interest statement: No potential conflict of interest was reported by the author(s).

Caffeine enhances performance regardless of fueling strategy; however, high carbohydrate availability is associated with improved training speeds compared with ketogenic diet.

14. Br J Nutr. 2025 Oct 14;134(7):578-588. doi: 10.1017/S0007114525105084. Epub 2025 Sep 18. Caffeine enhances performance regardless of fueling strategy; however, high carbohydrate availability is associated with improved training speeds compared with ketogenic diet. Burke LM(1), Merrell L(2), Heikura IA(1), Civil R(3), Sharma AP(4), Leckey JJ(5), McKay AKA(1). Author information: (1)Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, Australia. (2)Centre for Nutrition, Exercise and Metabolism, University of Bath, Bath, UK. (3)School of Sport, Exercise & Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, UK. (4)Victorian Institute of Sport, Melbourne, VIC, Australia. (5)South Australian Sports Institute, Adelaide, SA, Australia. The purpose of this study was to confirm reduced training metrics previously associated with a ketogenic low-carbohydrate (CHO) high-fat diet (LCHF) and investigate their attenuation with caffeine supplementation. At baseline, n 21 elite race-walkers followed a high CHO availability (HCHO) diet and performed a tempo hill session (14 km with a 450 m elevation gain). Athletes were then assigned to either the HCHO or LCHF in a parallel groups design for 3 weeks, where the 14 km tempo hill session was repeated each week. On weeks 2 and 3, in a randomised crossover allocation, all participants received 3 mg/kg caffeine or placebo (gum), 20 min before the session. Race-walking speed, heart rate, ratings of perceived exertion, blood metabolites and Stroop word-colour test metrics were collected. Although LCHF athletes walked faster at baseline compared with HCHO (P = 0·049), the HCHO group improved by week 2 (P = 0·009) and week 3 (P = 0·007), whereas the LCHF group was significantly slower in Week 1 (P < 0·001) and Week 2 (P = 0·026) compared with baseline. During the 14 km hill session, within-group analysis shows that athletes walked significantly faster (P = 0·010) and at a higher percentage of vVO2max (P = 0·007) when using caffeine compared with a placebo. Between-group differences remained present, with HCHO athletes walking at a higher percentage of vVO2max than those adhering to the LCHF diet (P = 0·035). No interaction between supplement treatment and dietary group occurred (P = 0·640). Caffeine supplementation partially reversed the performance impairment associated with an LCHF diet, but training quality remained lower than the combination of caffeine and high CHO availability. DOI: 10.1017/S0007114525105084 PMCID: PMC12676214 PMID: 40964913 [Indexed for MEDLINE]